Japan's World Cup squad departed their Florida training camp for Brazil on Saturday, confidence bolstered by two comeback victories but with plenty of work to do before their tournament opener.

Japan will face Ivory Coast next Saturday in their opening match at the World Cup, then meet Group C rivals Greece on June 19 and face Colombia five days later.

The Asian champions rallied from two goals down to edge Zambia 4-3 on Yoshito Okubo's stoppage-time goal after fighting back from surrendering the first goal to beat Costa Rica 3-1.

AC Milan striker Keisuke Honda scored twice against Zambia and Manchester United forward Shinji Kagawa netted one goal in each friendly as the Blue Samurai outlasted their rivals, scoring late each time to record a pair of triumphs.

"We always have to stay focused at a high level and stay motivated at a high level in matches and practices," Japan midfielder Yasuhito Endo said through a translator.

"After arriving in Brazil, we will feel more like, 'It's getting started now.' We have to maintain a good mood and good sense of urgency and that's when the players who have experienced the World Cup before can lead the rest of the team."

But Japan coach Alberto Zaccheroni has concerns after seeing his side surrender two goals from defensive mistakes to the 2012 African Cup of Nations winners in Friday's final warm-up for the World Cup.

"In terms of improving intensity, I need to talk with my players and figure out what to do," Zaccheroni said through a translator. "I'm not satisfied."

Having solved conditioning issues in the heat of humidity of Florida, Zaccheroni was more concerned about his team's tactical moves and how they might impose themselves upon an opponent at the World Cup.

"If we can play our game plan we can win," he said. "If we can't implement our plans, some bad things might happen.

"In the World Cup, we have to change our mindset and improve."

Zaccheroni gives Colombia a slight edge in the group but stressed that the second spot to advance into the last 16 was up for grabs.

"I think Colombia is more technical than the rest," he said. "This is a tough group. All the matches will be difficult."

The only injury concern is with long-time captain Makoto Hasebe, the Eintracht Frankfurt midfielder who did not play in either match in hopes he will be ready for the World Cup opener.

"I felt some stiffness, but overall I'm much better," Hasebe said. "There's nothing that I have to save. The World Cup is the priority."

Zaccheroni also said the defensive unit needs work after surrendering the first goals in each friendly, adding to the pressure upon defenders such as Southampton's Maya Yoshida.

"In the World Cup, there will be so many situations that we don't expect," he said. "In situations like that, it will be important for the goalkeeper and defenders to stay calm and control the match from behind."

Japan goalkeeper Eiji Kawashima, who only faced Costa Rica, said he is ready for the challenge that awaits in Brazil.

"I've been playing with firm mental determination, aiming for the World Cup," he said.

"All I have to do now is prepare well in the final training sessions, practice what we have prepared."